Something I find very interesting are the under the surface conditions in some bodies of water
https://www.bbc.co.uk/news/uk-scotland-highlands-islands-469...
237 karma · joined February 25, 2013
I currently have two hobby projects "in development". An bot trader (it broke even over 6 months with pretend money).
And a logic analyser using a Raspberry Pi Pico board and the excellent sigrok software - this project took a baby step to being non hobby when another dev found it and raised some issues.
Don't stop with the hobby projects
This is why I’ve retired and am just doing my own projects
I even spent 5 years working as an engineer at the BBC. There were plenty of BBC micros around performing ad-hoc tasks.